I have the 'absolute right' to pardon myself, says President Trump

Donald Trump has tweeted he has the "absolute right" to pardon himself over allegations of collusion with Russia, but insists he has "done nothing wrong".

He described the investigation by special counsel Robert Mueller into alleged Russian meddling as a "witch hunt".

The US president is being investigated to establish whether there was collusion between Russia and the Trump campaign during the 2016 US election.

"As has been stated by numerous legal scholars, I have the absolute right to PARDON myself, but why would I do that when I have done nothing wrong?," he wrote on Twitter on Monday.

"In the meantime, the never ending Witch Hunt, led by 13 very Angry and Conflicted Democrats (& others) continues into the mid-terms!"

The matter appeared to be playing on Mr Trump's mind as he tweeted a second post branding the investigation as "unconstitutional" twice within an hour - having misspelt counsel in his original tweet as "councel".

"The appointment of the Special Councel is totally UNCONSTITUTIONAL! Despite that, we play the game because I, unlike the Democrats, have done nothing wrong!" - he initially wrote.

During an appearance on ABC's This Week programme , Trump's lawyer Rudy Giuliani said there was nothing in the US Constitution to suggest that Trump could not pardon himself if he wanted to.

But he said doing so would have "tough" political ramifications.

"I think it would probably get answered by, 'gosh, that's what the Constitution says'. But the reason it won't is because then it becomes a political problem," he said.

"If the president were to pardon himself, he'll get impeached."